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UPCOMING MEETINGS

PUBLICATIONS

Issue 9, Spring 1994

PRODUCTS AND SERVICES

Four CD-ROM volumes of the DMSP F-11 SSM/I Brightness Temperature Grids for the Polar Regions are now available from NSIDC. These four volumes (12/3/91-11/30/92) extend the time series of gridded DMSP F-8 SSM/I passive microwave products produced and distributed by NSIDC. The F-11 SSM/I gridded products are in the same polar stereographic projection as that used for the products derived from the DMSP F-8 SSM/I data stream.

The F-11 SSM/I gridded products are being generated from the SSM/I Antenna Temperature tapes which NSIDC receives from Remote Sensing Systems. The data processing is performed with software that was ported from a VAX/VMS environment to a Silicon Graphics Incorporated (SGI) Challenge L server. A study comparing the DMSP F-8 SSM/I and DMSP F-11 SSM/I gridded products was conducted by investigators at both the Byrd Polar Research Center, Ohio State University, and the Cooperative Institute for Research in Environmental Sciences, University of Colorado ("Comparison of DMSP F-8 and F-11 Brightness Temperatures," submitted 15 April 1994, International Journal of Remote Sensing). The analysis demonstrated that although the two data sets "were highly correlated," [temperature] "corrections on the order of 1K should be applied" to adjust "the F-11 data to the F-8 baseline."

In addition to the minor dissimilarities between the F-8 and F-11 products, potential users of the DMSP F-11 SSM/I Brightness Temperature Grids for the Polar Regions should be aware of the following differences in the packaging of the two data sets:

F-8

band interleaved by pixel

three-dimensional 'raw' arrays PC/VAX byte order

oriented (0,0)as the upper right corner

F-11

one channel per file

Hierarchical Data Format (HDF) using Scientific Data Sets (SDS)

oriented (0,0) as the lower left corner

NSIDC chose to change the packaging for the F-11 data set because: 1) the majority of users responding to a survey distributed by NSIDC in 1991 (CDMS NOTES, No. 8, p. 3) wanted brightness temperature grids to be de-interleaved; and 2) Version 0 EOSDIS Project requires the DAAC to use HDF for data sets distributed to the user community.

A mailing list update form was sent to all SSM/I F-8 CD-ROM subscribers. We must purge our distribution list periodically, so if you are a subscriber and have not returned your update form, please do so right away to avoid a lapse in receipt of the SSM/I brightness temperature and sea ice concentration discs.

In the last issue of NSIDC NOTES (Issue 8, Winter 1994), we announced the prototyping effort to put non-image data into Hierarchical Data Format (HDF). The Historical Arctic Rawinsonde Archive (HARA), a time series of rawinsonde measurements over several Arctic regions, was chosen as a test data set.

The preliminary work is completed and those interested are encouraged to experiment with this new format. The data, and the software to extract it are now available on our ftp server (128.138.135.20, sidads.colorado.edu). Log into the server as anonymous, using your e-mail address as the password and then change directory to:

ftp> cd pub/DATA_SETS/DATA/HARA

This directory contains three sub-directories. The 'bin' directory has the executables, called 'pntshow', to extract the ASCII data from the HDF files. There are executables for four different platforms: SUN, SGI, HP9000 and DEC. The two other directories (1986.hdf and 1987.hdf) contain the data in HDF.

Streamer is a radiative transfer model that can be used for computing either radiances (intensities) or irradiances (fluxes) for a wide variety of atmospheric and surface conditions. Its interface is extremely flexible and easy to use. Streamer's major features are:

Fluxes (irradiances) may be computed using 2 or more streams, either broadband or narrow band.

Radiances (intensities) may be computed for any polar and azimuthal angles, using 4 or more streams. TOA (top-of- atmosphere) albedo or brightness temperatures are output along with the radiances.

Cloud forcing at the surface and TOA can be computed.

Gas absorption with overlapping gases and clouds are parameterized for 24 shortwave and 105 longwave bands. Gaseous absorption may be turned on or off.

Each computation is done for a "scene," where the scene can be a mixture of up to 8 individual cloud types, up to 4 overlapping cloud pairs, and clear sky.

Built-in atmospheric data include water and ice cloud optical properties, five aerosol optical models, four aerosol vertical profiles, five standard atmospheric profiles. Either standard or user-defined profiles can be used, or total column amounts of water vapor, ozone, and/or aerosols can be specified. Standard profiles include tropical, mid-latitude, and sub-Arctic.

Various built-in surface types may occur within the scene: open ocean (sea water), meltponds, bare ice, snow, green vegetation, and dry sand. (However, these types do not occupy different portions of the scene; i.e., their reflectance signatures are used to create a weighted average albedo for the entire scene.)

The user interface allows for looping over a range of values for up to ten variables at a time, and the users can easily customize their output.

Streamer may be obtained via anonymous ftp for implementation under UNIX or other operating systems. To obtain a copy of the Streamer User's Guide contact:

In order to provide better service and more flexible coverage for incoming telephone calls and electronic mail, we have established a central phone number and a central e-mail box for incoming communication to NSIDC User Services. Now that there are three of us, we can cover the phone and e-mail even when one or more of us is away from our desk or out of town.

During this time of growth at NSIDC, as we transition to more flexible and sophisticated request tracking and support systems, and as our data products and services become more complex, we ask your patience if we are not able to answer all your questions on the spot. We may have to get back to you after consulting with local experts on the topic of your question. Although we try to acknowledge receipt of phone or e-mail messages within 24 hours, occasionally it is not possible. Feel free to contact us again if you do not hear from us, but we hope this will be a very infrequent occurrence. If you should have to call or e-mail a second time to get our attention, please let us know it is your second attempt, so we can take steps to correct the cause of the problem.

Incoming requests to NSIDC, to the co-located EOSDIS NSIDC DAAC, or to the World Data Center-A for Glaciology are handled by Chris McNeave, Michelle Holm, or Claire Hanson, the User Services group. Scientific or computer support questions are referred to the appropriate NSIDC staff in those areas, or to other local experts if necessary. In order to ensure all requests are filled in a timely manner, the User Services group tracks involvement of other staff in each request.

Your comments and suggestions are welcome regarding the effectiveness of the User Services group in supporting your research data needs. Contact us at the phone or e-mail listed above at any time.

Please note that NSIDC DAAC is not the archive or distribution point for DMSP SSM/I swath (orbital) data. We distribute only the polar gridded brightness temperature and ice concentration SSM/I data. The official archive and distribution center for the swath data is:

ARCTIC SYSTEM SCIENCE (ARCSS)

Climate, hydrographic, nutrient, phytoplankton, and related data from the North East Water (NEW) Polynya Project of ARCSS will shortly be placed on CD-ROM by NSIDC. The "beta" version of this disc, targeted for production in mid-summer 1994, will be distributed to the NEW investigators for evaluation. After their evaluation, the data will become available to the Arctic research community. This is estimated to be mid to late 1995.

We are currently working with Doug Wallace, Marine Biological Laboratory, Woods Hole, MA, on finalizing the transfer of data collected during 1992 and 1993 in the Northeast Water Polynya to NSIDC. We are also working closely with Dr. Peter Minet, Marine Biological Laboratory, on acquiring his data from the NEW study.

The first in a series of ARCSS CD-ROMs, titled ARCSS/LAII Data Series Volume 1: Alaska North Slope Data Sampler, is still in the data collection phase. Two data sets will be added:

soil temperatures, depth of thaw measurements, and daily air temperatures for Barrow, Alaska, from the late 1940s through 1993 are being provided by Dr. Fritz Nelson, Rutgers University, and

temperature measurements on a transect along the Dalton Highway, 1975 to 1984, are coming from Dr. Richard Haugen, US Army CRREL (via Dr. Nelson). The inclusion of these data sets will aid in understanding the soil properties and climate of the North Slope of Alaska. We will keep you informed of the release date of the CD-ROM.

The NSIDC ARCSS group continues to work closely with the National Geophysical Data Center's (NGDC) Paleoclimate Division on management and distribution plans for the GISP2 core data. GISP2 investigators will shortly receive a joint letter from NSIDC and NGDC/Paleoclimate describing the current status of the archive and requesting deposit of any other GISP2 data that have been published. One planned method of distribution is a CD-ROM with GISP2 and other relevant core data sets, developed collaboratively by NSIDC and NGDC/Paleoclimate. This disc will include the core curator's inventory from the National Ice Core Laboratory, Denver, as well as any GRIP (Greenland Icesheet Program, the European ice coring project) data that are documented and deposited by GRIP investigators.

NSIDC ARCSS staff (Claire Hanson and Matthew Cross) will attend the September 1994 GISP2 PI Workshop to listen to GISP2 results and to discuss with the PIs our plans for management and distribution of GISP2 data.

UPCOMING MEETINGS

Room 322, Building RL-2, East Campus
University of Colorado, Boulder, CO
July 14 -15, 1994

Summary

NSIDC currently manages a bi-polar archive of 1-km AVHRR data, with coverage starting in April 1992 to the present. Areal coverage of both poles, including sea-ice regions, is nearly complete, and temporal frequency is 1/day or better. These data are currently available to the public (for small-data-volume requests, i.e., < 20 images/request) as NOAA Level 1B -format raw data, and HDF-format browse scenes. NSIDC would like to coordinate the development of algorithms for polar-wide geophysical measurements using the archive as a data base. This workshop is intended to provide an informal forum for presenting and discussing the several well-developed algorithms that exist. We would especially like to solicit presentations and review of the following algorithms:

Day 1 - 9:00 to 5:00 PM - presentations on the current status of various algorithms by the attendees;

Day 2 - 9:00 to 1:00 PM - half-day panel discussion for the ideas presented, considering approaches to extending algorithms to a 'production' basis. NSIDC would like to use willing attendees as a continuing 'information resource' as we begin implementation of processing routines which implement the algorithms.

Please let us know if you would like to attend, and if you would like to give a presentation. The workshop is intended to be informal, so short-notice additions to the agenda are not a problem.

PUBLICATIONS

A directory of library sources in the broad field of polar and other cold regions has been a project of the Polar [then Northern] Libraries Colloquy since the first edition was published in 1975. This, the third edition, was edited by Martha Andrews, Institute of Arctic and Alpine Research, Ann Brennan, WDC/NSIDC, and Liisa Kurrpa, Arctic Centre, University of Lapland.